Depends.
Extreme ENPs often appear random and inconsistent.
When they are more balanced, I think ENFPs have better use of their shadow ISTJ. That means, they can accumulate great amounts of information with great precision - and then apply the ENFP Ne to produce something creative of it. Their worst errors are usually in final conclusions and summaries (the Fi comes along to bring idealism and utopia). However, they can be the most accurate and factual in their presentations, using the ISTJ-mode.
With ENTP - they are great on the creative side, but during the accumulation of information they just misinterpret or remember some things wrong (using ISFJ). Therefore, they cannot even realize how wrong are some of their statements during presentations. But on the long run their true and practical ENTP creativity pays off and they produce a lot of useful results (among some failures).
I would claim ENPs are the most creative of all types, in general, but also the worst to present their own ideas to the status quo. The best way for them is to just implement their theories and prove them in practice. It is difficult for them to provide conceptual proofs (nasty INTPs never trust it due to lack of intuition).
They are definately prone to errors, and the extreme peer judgement may destroy them (if they get bashed for too many fails). Still, there's usually valuable insight even in their errors.
